Article IV: On the Admission or Profession of Doctrine Which Is Dangerous to Faith

780. Doctrines dangerous to faith. - Besides the sin of infidelity, which is directly opposed to faith and brings with it the loss of faith itself, there are other things indirectly opposed to it. For virtue prohibits not only that by which it is destroyed, but also that anyone expose himself or others to the danger of losing it or of not obtaining it. Hence occasional causes which lead to its loss are prohibited. Therefore the virtue of faith itself prohibits under grave obligation not only the external occasions of which we have already spoken, namely, the reading of writings against faith, communication and friendship with infidels, heretics, apostates, impious persons, indifferentists, etc., attendance at their societies or schools, participation in their rites, cooperation with infidelity and heresy, if they constitute a notable danger for faith, but also:

1. internal adherence to propositions censured by the infallible authority of the Church as erroneous and false or rash, because such propositions are logically connected with the denial of faith, or at least dispose and lead to this denial; likewise the denial of facts infallibly defined by the Church which are connected with revealed truths, because this denial leads to the denial of the dogma itself. These contain a grave injury against the authority of the Church, and are a sin directly opposed to the virtue of studiousness, indirectly against faith (Vatican Council, sess. 3, c. 4; prop. 7 Mod.; can. 1324; letter of Pius IX to the bishop of Munich, December 11, 1862);

2. doctrinal assertion before others or defense of the preceding things (can. 1399, § 6), or even of propositions which are infallibly censured as savoring of heresy or error, evil-sounding, offensive to pious ears, scandalous (in doctrine): these are directly a sin against modesty in speaking, indirectly against confession of faith when they dispose others to sinning against faith (can. 1399, § 6). Hence the Church urges this under penalties (can. 2317);

3. indeed, per se, the denial of those things which, although not with infallible authority, nevertheless with the authority of the Roman Pontiff as head of all the Churches, or by the Roman Congregations, or by the consensus of all theologians in matters of faith and morals, are taught as certain or to be held: for per se it involves rashness because it spurns a doctrine, not infallible, but practically certain (Pius IX to the bishop of Munich, December 21, 1863; prop. 8 Mod.).

It is said: per se, because while the Church does not teach with infallible authority, the doctrine proposed is not of itself irreformable; hence, if per accidens, nevertheless in a very rare case, after an altogether diligent examination, most grave reasons against the doctrine thus proposed seemed present to someone, it would be lawful without rashness internally to suspend assent; yet externally, on account of reverence toward the Church, an obsequious silence would be required.